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Subject[tip: x86/entry] x86/xen: Split HVM vector callback setup and interrupt gate allocation
The following commit has been merged into the x86/entry branch of tip:

Commit-ID: fad1940a6a856f59b073e8650e02052ce531154c
Gitweb: https://git.kernel.org/tip/fad1940a6a856f59b073e8650e02052ce531154c
Author: Vitaly Kuznetsov <vkuznets@redhat.com>
AuthorDate: Tue, 28 Apr 2020 11:38:22 +02:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 13 May 2020 21:13:54 +02:00

x86/xen: Split HVM vector callback setup and interrupt gate allocation

As a preparatory change for making alloc_intr_gate() __init split
xen_callback_vector() into callback vector setup via hypercall
(xen_setup_callback_vector()) and interrupt gate allocation
(xen_alloc_callback_vector()).

xen_setup_callback_vector() is being called twice: on init and upon
system resume from xen_hvm_post_suspend(). alloc_intr_gate() only
needs to be called once.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200428093824.1451532-2-vkuznets@redhat.com

---
arch/x86/xen/suspend_hvm.c | 2 +-
arch/x86/xen/xen-ops.h | 2 +-
drivers/xen/events/events_base.c | 28 +++++++++++++++++-----------
3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/arch/x86/xen/suspend_hvm.c b/arch/x86/xen/suspend_hvm.c
index e666b61..5152afe 100644
--- a/arch/x86/xen/suspend_hvm.c
+++ b/arch/x86/xen/suspend_hvm.c
@@ -13,6 +13,6 @@ void xen_hvm_post_suspend(int suspend_cancelled)
xen_hvm_init_shared_info();
xen_vcpu_restore();
}
- xen_callback_vector();
+ xen_setup_callback_vector();
xen_unplug_emulated_devices();
}
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 45a441c..1cc1568 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -55,7 +55,7 @@ void xen_enable_sysenter(void);
void xen_enable_syscall(void);
void xen_vcpu_restore(void);

-void xen_callback_vector(void);
+void xen_setup_callback_vector(void);
void xen_hvm_init_shared_info(void);
void xen_unplug_emulated_devices(void);

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 3a791c8..eb35c3c 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -1639,26 +1639,30 @@ EXPORT_SYMBOL_GPL(xen_set_callback_via);
/* Vector callbacks are better than PCI interrupts to receive event
* channel notifications because we can receive vector callbacks on any
* vcpu and we don't need PCI support or APIC interactions. */
-void xen_callback_vector(void)
+void xen_setup_callback_vector(void)
{
- int rc;
uint64_t callback_via;

if (xen_have_vector_callback) {
callback_via = HVM_CALLBACK_VECTOR(HYPERVISOR_CALLBACK_VECTOR);
- rc = xen_set_callback_via(callback_via);
- if (rc) {
+ if (xen_set_callback_via(callback_via)) {
pr_err("Request for Xen HVM callback vector failed\n");
xen_have_vector_callback = 0;
- return;
}
- pr_info_once("Xen HVM callback vector for event delivery is enabled\n");
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
- xen_hvm_callback_vector);
}
}
+
+static __init void xen_alloc_callback_vector(void)
+{
+ if (!xen_have_vector_callback)
+ return;
+
+ pr_info("Xen HVM callback vector for event delivery is enabled\n");
+ alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, xen_hvm_callback_vector);
+}
#else
-void xen_callback_vector(void) {}
+void xen_setup_callback_vector(void) {}
+static inline void xen_alloc_callback_vector(void) {}
#endif

#undef MODULE_PARAM_PREFIX
@@ -1692,8 +1696,10 @@ void __init xen_init_IRQ(void)
if (xen_initial_domain())
pci_xen_initial_domain();
}
- if (xen_feature(XENFEAT_hvm_callback_vector))
- xen_callback_vector();
+ if (xen_feature(XENFEAT_hvm_callback_vector)) {
+ xen_setup_callback_vector();
+ xen_alloc_callback_vector();
+ }

if (xen_hvm_domain()) {
native_init_IRQ();
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